This invention is directed to a laminated composite structural fitting and method for making the fitting, comprised of forming a plurality of one or more layers each successively folded to overlap at the end and at the corners to provide maximum corner strength.
In aircraft construction there are a number of locations in which loads must be transferred from one structural member to another. A typical illustration of a critical area in aileron construction is the transfer of loads from the aileron actuator fittings to the front spar, the rib, and to the aileron surfaces. Ribs are provided at each hinge and at each actuator station to share in carrying this load and to redistribute it onto the surface panels. The fitting which inter-engages between the hinge and actuator structure and the rib is an important structure for the transfer of the load.
The prior art fittings and methods of construction of such fittings comprises the machining, casting or forging metals to the desired geometry. After that, composite fittings were created, but these have been formed by high pressure compression molding of chopped fiber and thermosetting resin in matched precision steel dies. The fibers are often fiber-glass, graphite, or Boron fibers and are chopped at appropriate lengths for molding in a particular mold structure. Furthermore, in such structures a formed oriented glass, graphite, or Boron surface inlay is often used to define the outer stress surfaces. However, since the fibers are chopped they are randomly organized, and not organized in a direction for optimum material characteristics. Other multi-layer structures have not employed interleaving which interlaces or interleaves panels around a corner for stress distribution around the corner for an optimum structural composite fitting.
Aircraft need structure with maximum strength and minimum weight with load carrying fittings of this nature serving essential load transfer needs and contributing minimum weight to the aircraft structure.